Technetium-99m, referred to hereinafter as 99mTc, is one of the most widely used radioactive tracers in nuclear medicine diagnostic procedures. 99mTc is used routinely for detection of various forms of cancer, for cardiac stress tests, for assessing the densities of bones, for imaging selected organs, and other diagnostic testing. 99mTc emits readily detectable 140 keV gamma rays and has a half-life of only about six hours, thereby limiting patients' exposure to radioactivity. Because of its very short half-life, medical centres equipped with nuclear medical facilities derive 99mTc from the decay of its parent isotope molybdenum-99, referred to hereinafter as 99Mo, using 99mTc generators. 99Mo has a relatively long half life of 66 hours which enables its world-wide transport to medical centres from nuclear reactor facilities wherein large-scale production of 99Mo is derived from the fission of highly enriched 235Uranium. The problem with nuclear production of 99Mo is that its world-wide supply originates from five nuclear reactors that were built in the 1960s, and which are close to the end of their lifetimes. Almost two-thirds of the world's supply of 99Mo currently comes from two reactors: (i) the National Research Universal Reactor at the Chalk River Laboratories in Ontario, Canada, and (ii) the Petten nuclear reactor in the Netherlands. In the past few years, there have been major shortages of 99Mo as a consequence of planned or unplanned shutdowns at both of the major production reactors. Consequently, serious shortages occurred at the medical facilities within several weeks of the reactor shutdowns, causing significant reductions in the provision of medical diagnostic testing and also, placing great production demands on the remaining nuclear reactors. Although both facilities are now active again, there is much global uncertainty regarding a reliable long-term supply of 99Mo.